Path: csiph.com!newsfeed.hal-mli.net!feeder3.hal-mli.net!newsfeed.hal-mli.net!feeder1.hal-mli.net!border3.nntp.dca.giganews.com!Xl.tags.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local2.nntp.dca.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail NNTP-Posting-Date: Sun, 25 Aug 2013 20:04:07 -0500 From: Randy Yates Newsgroups: comp.arch.embedded Subject: Re: Routing signals under crystals Organization: Digital Signal Labs References: <9e3e5359-dafb-4c4c-8225-05565253a927@googlegroups.com> <87a9k6wlmn.fsf@digitalsignallabs.com> Date: Sun, 25 Aug 2013 21:04:07 -0400 Message-ID: <87sixxtg8o.fsf@digitalsignallabs.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.2 (gnu/linux) Cancel-Lock: sha1:cjHiYRjh1F9stK1acygMSG331G8= MIME-Version: 1.0 Content-Type: text/plain Lines: 27 X-Trace: sv3-6v6zAyohc7q3DKIa4sr6tgoD4m6R5rn+kNTATB3Id+T8C+G32U6mYLDj41xsyaZr55+uP7njQW05IDl!8+JiLqCjbkUqk6xWg3Ugth+f/o8zbeEuGaL8CJMf2mHGtY+CWkFxPygijFiNjlWrYpBCB8LIjw== X-Complaints-To: www.supernews.com/docs/abuse.html X-DMCA-Complaints-To: www.supernews.com/docs/dmca.html X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 X-Original-Bytes: 2407 Xref: csiph.com comp.arch.embedded:13190 rickman writes: > On 8/24/2013 10:27 PM, Randy Yates wrote: >> rickman writes: >> >>> On 8/24/2013 1:16 AM, Mark Borgerson wrote: >>>> >>>> I agree with that. It's probably even less of a problem when the >>>> fastest clock on the board is in the internal processor of the >>>> SD card logging the data. Writing to an SD card can generate quite >>>> a burst of EMI, but I haven't seen large effects on crystal behavior. >>> >>> Really? I've never seen significant EMI directly generated by any >>> chip. >> >> How do you know where it's coming from? Do you have screen rooms, >> antennae, spectrum analyzers, etc., like FCC testing centers do? > > Lol, if you have EMI, you fix the board and it goes away, that shows > it wasn't the chip... Same with the SD card. Replace the SD card > with a different brand and the EMI should change or go away. Sure. But remember all those funny interactions you were talking about? -- Randy Yates Digital Signal Labs http://www.digitalsignallabs.com